Influence of pore water chemistry on the swelling behavior of compacted clays

• Published in: Applied clay science Vol. 15; no. 5; pp. 447 - 462
• Main Authors: Abdullah, Waddah S, Alshibli, Khalid A, Al-Zou'bi, Mohammed S
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.12.1999; Amsterdam Elsevier Science; New York, NY
• Subjects: Atterberg limits; cation exchange; compaction; Earth sciences; Earth, ocean, space; Exact sciences and technology; expansive clays; Mineralogy; Silicates; swelling; compaction; Atterberg limits; swelling; expansive clays; cation exchange; cation exchange capacity; ion exchange; X-ray diffraction; TEM data; Clay soils; interatomic bond; grain size; pore water; pH; water content; sheet silicates; silicates; clay minerals; transmission electron microscopy; soils
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/S0169-1317(99)00034-4

The influences of the exchange complex and pH of the solution used for cation saturation on Atterberg limits, compaction, and swelling potential of a compacted clay were investigated. The study involved transforming the exchange complex from a heterogeneous to a homogeneous one so that a frame of reference can be set for the clay behavior under such an ideal condition. The employed method for altering the exchange complex successfully yielded homo-ionic clay. The introduction of different species of cations gave rise to different particles associations. When introduced to the tested clay, potassium cations bond its particles with a rather strong bond (K-linkage), causing a drastic decrease in the specific area of the clay (about one-fourth of its untreated specific area), a decrease in the CEC, as well as a drastic decrease in the swell potential. For example, the swell pressure decreased from 1.87 kg/cm 2 for the untreated samples to 0.4 kg/cm 2 for the K-treated samples (under the same conditions). Also, the swell potential vs. time relationships can be modeled accurately using a rectangular hyperbola.